1. Field of the Invention
The present invention relates to an image-forming material and method, and more particularly, to a method for forming thin layer images by peel-apart-development of materials having a light-sensitive composition and a thin layer of which the adhesive properties thereof are changed by exposure to actinic radiation.
2. Description of the Prior Art
Image forming methods using the wet development of a thin layer or coating (e.g., a metal thin layer prepared using a vacuum plating method) and a light-sensitive resin, in combination for photographic images, printing images and relief images are widely known. Wet development methods after image-wise exposure, and materials therefor, are disclosed in Japanese Patent Publications Nos. 38,453/74 and 5,053/75, U.S. patent application Ser. No. 205,861, filed Dec. 8, 1971, now U.S. Pat. No. 4,113,494 (corresponding to Japanese Patent Application (OPI) No. 65,928/73) and Japanese Patent Application (OPI) No. 15,422/76. According to these methods, images can be obtained by exposing through an original to actinic radiation a light-sensitive material comprising a support having provided thereon a thin layer such as a metal layer and a light-sensitive layer to imagewise expose the light-sensitive layer according to the original image, and then developing the material to remove the exposed or unexposed areas of the light-sensitive layer, and furthermore, processing the material with a liquid capable of dissolving the thin layer to dissolve and remove the thin layer in the areas corresponding to the areas of the light-sensitive layer removed. These methods are not advantageous because two complicated wet processing steps, that is, removal of the unexposed light-sensitive layer and removal of the thin layer, are necessary. Materials and methods for improving the two-bath wet processing methods are disclosed in U.S. patent application Ser. No. 205,860, filed Dec. 8, 1971, now abandoned (corresponding to Japanese Patent Application (OPI) No. 65,927/73), U.S. patent application Ser. No. 350,372, filed Apr. 12, 1973 (corresponding to Japanese Patent Application (OPI) No. 2,925/75) and U.S. patent application Ser. No. 571,817, filed Apr. 25, 1975, now U.S. Pat. No. 4,008,084 (corresponding to Japanese Patent Application (OPI) No. 139,720/75). According to these methods, thin layer images can be obtained by exposing through an original to actinic radiation a light-sensitive material comprising a support having provided thereon a thin layer and a light-sensitive layer to imagewise expose the light-sensitive layer according to the original image and then processing the material with a developing solution to simultaneously remove either the exposed or unexposed areas of the light-sensitive layer and the thin layer.
These wet developing methods have the disadvantages that processing operations, for example, temperature control of the developing solution or exchange of the developing solution due to the fatigue thereof, are complicated and discharge of organic solvents from the developing solution causes pollution problems, because they include step or steps for removing the light-sensitive layer and the thin layer utilizing the difference in solubilities of the exposed and unexposed areas in the developing solution.
For the purposes of eliminating some of the defects of the wet developing methods, peeling-apart development methods and materials, which are considered to be dry developing methods, are disclosed in U.S. Pat. Nos. 3,353,955 and 3,770,438 and Japanese Patent Publications Nos. 9,663/63 and 43,126/73, and Japanese Patent Applications (OPI) Nos. 336,323/72 and 123,021/74. According to these methods, positive images and negative images can be obtained by exposing a light-sensitive material comprising a support having provided thereon a light-sensitive layer and a transparent thin synthetic resin film through an original to actinic radiation to imagewise expose the light-sensitive layer corresponding to the original image, and then peeling apart the transparent synthetic resin film. Other methods are known which comprise exposing through an original to actinic radiation a light-sensitive material comprising a transparent thin synthetic resin film having coated thereon a light-sensitive layer which is then provided on another support such as a support of a metal, glass, a synthetic resin sheet or paper to imagewise expose the light-sensitive layer corresponding to the original image, and then peeling apart the transparent synthetic resin film to provide negative images on one support and positive images on the other support. These peel-apart-development methods are interesting because of the ease of the developing operation and no pollution problems occur.
In the materials and methods as disclosed in the prior art, only the exposed or unexposed areas of the light-sensitive layer are removed from the support which has a larger mechanical strength by peeling apart the transparent synthetic resin film to form images comprising the light-sensitive composition. Further, U.S. patent application Ser. No. 571,817, filed Apr. 25, 1975 (corresponding to Japanese Patent Application (OPI) No. 139,720/75) discloses providing a metal thin layer between a support and a light-sensitive layer and selectively removing the light-sensitive layer corresponding to original image areas from the metal thin layer by a peel-apart-developing method. According to this method, the metal thin layer corresponding to the original image areas cannot be peeled apart with the light-sensitive layer from the support because of the adhesion between the peel-apart sheet and the light-sensitive layer, and the adhesion between the light-sensitive layer and the metal thin layer act together so that only the light-sensitive layer corresponding to original image areas is removed from the metal thin layer. A method in which a thin layer is selectively removed with a light-sensitive layer after imagewise exposure to form metal thin layer image areas corresponding to the original image areas by using a metal thin layer capable of being peeled apart from a support and having a weaker mechanical strength than the support has not been found.